1. Field of the Invention
This invention relates to resin concrete molded products having definite shapes, such as waterproof pans, kitchen counters, bathtubs and wall coverings for bathrooms, and a method of making the same.
2. Description of the Prior Art
Resin concrete is a building material made by bonding an inorganic or organic filler with a synthetic resin. As is well known, it shrinks heavily during soldification, and is low in strength, particularly when stretched or bent; it is impossible to make molded objects, such as waterproof pans, kitchen counters, bathtubs and wall coverings for bathrooms, by using resin concrete alone. Therefore, all the molded products of resin concrete known in the art have been of the laminated construction in which one or both surfaces of a resin concrete layer are reinforced with fiber reinforced plastics. This is the reason for the warp of molded products. Consequently, the molded product is likely to be warped, and if it is not warped, it has a very low degree of dimensional accuracy. Moreover, if the thickness of the resin concrete layer in the molded product is too small, the resin concrete layer is not sufficiently strong, but a crack which reduces or eliminates the commercial value of the molded product develops in any bent corner thereof due to the local concentration of stress therein during the shrinkage of the resin concrete. Accordingly, it has heretofore been essential that any molded product of resin concrete have a sufficiently thick resin concrete layer to prevent any such cracking thereof. Thus, all the molded products of resin concrete known in the art are not only inferior in dimensional accuracy, but are also extremely heavy. In all known molded products of resin concrete, their resin concrete layer has a thickness/maximum length ratio which is greater than 25/1,000, and there is not known any such molded product having a layer of resin concrete with a smaller thickness relative to its maximum length.